Field
The invention generally relates to display devices, and more particularly, to touch sensing display devices including touch force sensors.
Discussion of the Background
A touch sensing unit (e.g., a touch screen panel) is an input device that allows a user's instruction to be input by selecting particular content displayed on the screen of a display device or the like with a user's hand or an object. The touch sensing unit may be formed on the display device and may convert a touch location or the like into an electrical signal. Specifically, the user's hand or the object may directly contact the touch sensing unit at the touch location. Since such a touch sensing unit may be substituted for a separate input device (such as a keyboard or mouse) connected to the display device, applications for touch sensing units have been growing. The touch sensing unit may include components such as a resistive overlay touch sensing unit, a photosensitive touch sensing unit, a capacitive touch sensing unit, and the like.
Among those touch sensing units, the capacitive touch sensing unit may include a touch location sensor and a touch force sensor. The touch location sensor may detect a touch location by sensing change in capacitance when the object (or the user's hand) comes in contact with the touch sensing unit, and may convert the touch location into an electrical signal. The touch force sensor may detect a touch force by sensing the magnitude of change in capacitance when the object (or the user's hand) comes in contact with the touch sensing unit, and may convert the touch force into an electrical signal.
Generally, the touch force sensor may be manufactured separately from the display device, and then may be attached on a bottom surface of the display device so as to measure the magnitude of the touch force on the display device. In this case, however, the thickness of the display device increases due to the thickness of the touch force sensor, and the manufacturing cost may increase. In particular, where the touch force sensor is attached to the bottom surface of the display device, additional thickness, cost and assembly time is required for cushion layers typically provided on both sides of the touch force sensor. Further, touch force sensors attached to the bottom surface of the display device are typically fabricated as an aluminum foil plus a PI (polyimide) film and thus include the thickness associated therewith
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concepts, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.